The granting of independence to the Bank of England in 1997 was the rock on which Gordon Brown built his reputation of economic competence. With so many other aspects of New Labour's economic record looking shaky, surely the Prime Minister would not be so foolish as to chip away at this foundation stone?
Some are picking up disturbing signals. The first of these was the announcement late on Wednesday evening of the premature departure of Sir John Gieve as deputy governor of the Bank of England.
It was no secret that Downing Street had been unhappy with the Bank's handling of the implosion of Northern Rock. And Sir John, by virtue of his specific responsibility at the Bank for overseeing financial stability, had taken much of the political flak for that failure. He was given quite a roasting by the Treasury Select Committee last autumn. It is perfectly true that Sir John, with no in-depth market or economic expertise, might not have been best suited to this role. And he was not the first choice of the Bank's Governor, Mervyn King, when he was appointed two years ago. Yet under the 1988 Bank of England Act, deputy governors are not supposed to be fired. Some are interpreting this sudden personnel change, rightly or wrongly, as a sign that this is no longer the case.
The second worrying sign is the release yesterday by the Treasury of details of a new banking reform bill. The Treasury says this bill will give the Bank of England enhanced responsibilities for rescuing stricken retail banks such as Northern Rock. Yet at the same time, the bill will establish a "Financial Stability Committee" to advise the Governor in times of crisis. So is this another stealthy political encroachment on the Bank's independence?
We shall have to wait for the details of the committee's composition and personnel. In the meantime it is perfectly possible for ministers to make the case that there is no harm in giving the Bank of England another source of expert advice. And it is difficult for Mr King to reject it without appearing arrogant or ungracious.
But the Government should be cautious. Even if the Bank of England remains as free today to exercise its own judgement as it was in 1997, it is the outward perception of independence that matters most for the financial markets and the public, in terms of the credibility of monetary policy. With the economy facing its most testing times in two decades, ministers jeopardise that perception at their peril.